1. Technical Field
The present invention relates to a compressor control device for a refrigerator and a method thereof More particularly, it relates to a compressor control device for a refrigerator and a method thereof, which sense a momentary power failure.
2. Related Art
A refrigerator includes a converter for converting an alternating current (AC) power to a direct current (DC) power, a power-supply unit which receives the direct current power from the converter and converts the direct current power to first and second direct current voltages, and a controller which receives the first direct current voltage from the power-supply unit and determines an operation frequency of a compressor according to a refrigerating compartment condition and a freezing compartment condition and generates a control signal.
In operation, if a power voltage is suddenly turned off during a normal operation and is then turned on, a power applied to a compressor becomes reduced during a power failure duration, thereby lowering revolutions per minute (rpm) of the compressor. In other words, if a momentary power failure occurs, a power applied to a compressor becomes reduced during the power failure duration, thereby lowering revolutions per minute of the compressor.
For example, if the power failure is maintained during 500 milliseconds (msec), the compressor revolutions per minute (rpm) drops from 3600 rpm before the power failure to 2000 rpm. Under this condition, if the power is provided again to the compressor, overcurrent is applied to the compressor, so that the compressor may be damaged.
In more detail, the compressor nearly maintains a normal revolutions per minute by inertia during a short time period after the power failure, but quickly drops its revolutions per minute if the time period after the power failure continues. Accordingly, if the power is provided again under the condition that the compressor nearly maintains the normal revolutions per minute, the compressor is not damaged. However, if the power failure time extends beyond the short time period, the revolutions per minute of the compressor becomes considerably lower than the normal revolutions per minute. In this case, if the power is provided again to the compressor, overcurrent is applied to the compressor, thereby possibly causing the compressor to become damaged.
I have found that the aforementioned refrigerator cannot effectively protect the compressor when the power failure occurs. Efforts have been made to improve refrigerators. For example, there exists a Japanese Patent Unexamined Publication No. sho 56-113969, published on Sep. 8, 1981 (hereinafter Japanese Patent '969).
While Japanese Patent '969 provides advantages, I note that it fails to adequately provide a compressor control device for a refrigerator, and method thereof, which efficiently and conveniently protects the compressor without an unnecessary delay of a power-on time.